Hinge fo-r



UNITED STATES PATENT CEEICE.

DAN. A. HOYT AND PETER W'. BULKELEY, OFDANBURY, CONNECTICUT. l

HINGE FOR DOO-RS, 85C., DENOMINATED THE HELICAL SPRING-JOINT HINGE.

Specification of Letters Patent No. 721, dated April 28, 1838.

To all whom t may concern Be it known that we, DANIEL A. Hoifr and PETER W. BULKELEY, of Danbury, in the county of Fairfield and State of Connecticut,

have invented a new and useful hinge for doors, which we denominate the Helical Spring-Joint Hinge, and we do hereby declare that the following is a full and exact description thereof.

The design of this hinge is, while it operates as an ordinary door hinge, to cause the door to close, by the action of the helical spring, which is coiled around the joint pin of the hinge.

In the accompanying drawing a, a, a, are the knuckles of the hinge; and b, b, is the helical spring, which is coiled around the joint pin, in the space, or spaces, left between the knuckles, for that purpose. These springs may be made of any suitable metal, brass, or steel, however, being preferred.

Vhen two or more portions of the joint pin have a spring upon them, the wire may still be in a single piece, causing it to pass Y over the intermediate knuckle `as shown at c,l the eXtreme ends bearing upon the leaf of the hinge as shown at cl, d, or the ends being confined in any other way which may be preferred. u

What we claim as our invention, and desire to secure by Letters Patent, is

DANIEL A. HOYT. j PETER W. BU'LKELEY.

Vitnesses:

STEPHEN BATES, SiLAs H. HIoKoK. 

